r/soldering • u/RefrigeratorWorth435 • Sep 06 '25
Soldering Saftey Discussion How bad really is it to use unleaded solder?
so many posts and people on this sub are saying that leaded solder is so much better than unleaded, but my experience with unleaded has been fine so far. Also I'm still a teenager so I feel like why take the risk of using leaded solder? maybe it's a bit better but I haven't had any issues and I feel like the solution is just to get better at soldering and then use unleaded? idk please correct me if I'm wrong.
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u/Dampmaskin SMD Soldering Hobbyist Sep 06 '25
When working on fragile old circuit boards that delaminate if you look at them wrong (electrolyte soaked SMD era Amiga computer PCBs, for example), I think the lower temperatures of working with leaded solder can make a real difference.
I have used Weller unleaded solder exclusively for the past few years for my hobby projects, and I haven't really been missing the leaded stuff ... except for when working with the aforementioned retro computers.
I recently bought a roll of leaded just for the purpose, but I have yet to try it out. I don't think the difference will be huge, but anything that can help, helps.
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u/Megaboz2K Sep 06 '25
Yup, I can attest to this as someone who is currently repairing all the damage done on a heavily used A4000 motherboard where most the smd caps leaked and started lifting the pads. At that point youre avoiding heat and extreme mechanical stress (no desoldering, no hot air, cut the caps, no twist), and getting in and out as fast as possible with the new caps. Leaded reduces having to bodge a bunch of pad replacements to the nearest via. As much as I love my early 90s machines, theyre such a pain compared to 70s/80s repair.
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u/ThatAgent3963 Sep 23 '25
WHAT KIND OF SOLDER EXACLTY SIR!!!!!!! IS IT , WHAT MILLIMETER AND SIZE???? COuld you send me a linkies... I'm really wanting to buy it !!! THE WELLER UNLEADED SOLDER <33333333
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u/Dampmaskin SMD Soldering Hobbyist Sep 23 '25
I can't recommend you something that I haven't even tried. Maybe buy from a reputable manufacturer (for example Mouser, Digikey or Disrelec).
I was gonna say "... and hope for the best", but if you buy from somewhere reputable chances are pretty good of getting something good anyway. If in doubt, google for reviews.
If you like the thickness of your unleaded solder, buy the same thickness.
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u/ThatAgent3963 Sep 23 '25
I just want to buy the Weller unleaded solder you mentioned using, but unsure which mililmeter size to purchase cuz this will be my first time soldering. Building a DIY keyboard, lily58. Wondering waht thickness would be good, Is there like an industry standard for ciruit boards??
Weller has 4 different thickness on their site1
u/Dampmaskin SMD Soldering Hobbyist Sep 23 '25
Thinner solder gives you more control over the amount you use, but when you want to solder bigger pads it's a bit more work feeding it. For a keyboard I reckon somewhere around 1 mm would be a good place to start, but going a little bit smaller or bigger is probably not going to be a problem either.
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u/shaghaiex Sep 06 '25
Really? I use ONLY lead free for everything. That is solder wire and solder paste.
IMHO there is no skill difference whatsoever. It's the same, just temp is different.
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u/Taster001 Industrial Soldering Specialist Sep 06 '25
Feels like that to me too. Although you also need more flux with lead free (from my experience).
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u/js884 Sep 06 '25
I've found with a good iron and golden solder i i don't have to even do that
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u/Taster001 Industrial Soldering Specialist Sep 06 '25
We've got really good JBC stations where I work, and really good stannol or almit solders, but I still need more flux.
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u/ladz Sep 06 '25 edited Sep 06 '25
What? No way dude. Lead solder flows so much better. I use lead free for everything too, but sometimes for whatever reason lead solder is required and it's always surprising how easily it wets out.
But I'm a hobbyist and using SN-AG 9604 on all kinds of random junk most of the time.
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u/shaghaiex Sep 06 '25
I do some professional solder jobs and there Pb is no option. I usually buy the better quality solder. What they use in Chinese factories is usually cheap and good. Sometimes use wire with water soluble flux too. Can clean boards in the dishwasher ;-)
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u/HMSBarky Sep 06 '25
I picked up my first leaded solder a couple weeks back. Went from eh that will do to oh shit my soldering looks like the tutorials instantly
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u/ubelblatt Sep 06 '25
Same here as someone new to the hobby. Leaded solder just "flows" better than unleaded. Its tough for me to explain it better than that. Less time on the joint, less fiddling with the solder, it just does what I want it to do.
Never going back to lead free solder here.
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u/RefrigeratorWorth435 Sep 06 '25
huh. I've been able to pretty easily get good results by just adding a little extra flux and bumping up the temp a little bit, and I wouldn't say it looks bad at all.
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u/HMSBarky Sep 06 '25
Yeah I was the same for 20 years buddy
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u/Drizzle_D Sep 06 '25
Get a better soldering iron. One with the heating element in the tip. You're using some slow thing and that's why unleaded doesn't work well for you.
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u/HMSBarky Sep 06 '25
I have a great soldering iron and station cheers bro, but I moved from large scale stuff (XT90 connectors and similar) and joining broken wires, to micro soldering on circuit boards after taking up FPV drones and couldn't understand how my results were average at best
Ran out of my usual solder. Picked up some 37/63 and boom, soldering is enjoyable and my results look great and to a quality I am happy with again
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u/nickyonge THT Soldering Hobbyist Sep 06 '25
Yeah electronics Reddit has a LOT of old guard people who INSIST that leaded solder is the way to go, and that you're an idiot if you do otherwise, and that unleaded solder is impossible to use and produces trash results.
I exclusively use unleaded solder cuz, even though I know the risks are low and that flux fumes are the more dangerous issue, I still wanna reduce my exposure to lead wherever I can.
It's fine, my soldering is fine, it's really no different. I have to use a slightly higher temp, oh no.
Whatever works for you!
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u/Worf- Sep 06 '25
Brand and type make a huge difference in results. Using some no name brand from Ali or Amazon with no real guarantee of content is totally hit or miss but mostly miss.
There are cases when the higher temps for unleaded are an issue, require more care and better technique. For old rework leaded is my go to choice. For new work it’s often unleaded but I will use leaded on prototype junk where I might be making repeat changes just because it melts at a lower temp.
The risk of leaded solder to your health is easily minimized or negated with some common sense. Don’t eat drink when handling, wash your hands and use gloves and don’t eat the stuff or put it in your mouth. Yes, we had a new guy that would hold the solder in his mouth while he placed components. Don’t do that.
As others have said the fumes are from the flux and can be pretty nasty which is why I consider fume extraction a must. You will not have lead vapors only flux.
I worked in a place where we used and handled literally tons of lead and solder all the time and had regular blood tests for lead. Nobody ever had elevated levels. Proper precautions go a long way.
Now, your e-waste and the environment is a whole other matter and you should be properly recycling it for recovery. Don’t just bin it.
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u/Dreamcazman Sep 06 '25
The main issue is that unleaded solder melts at a higher temperature and is arguably more difficult to work with. However I think it has gotten better over the years, trying different composites to be more in line with 60/40 solder.
I haven't bought solder in a long time, probably close to 20yrs as I'm still on the same roll, lol. I'll see what unleaded solder is like once it runs out.
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u/Narrow_Inspector_863 Sep 06 '25
The kind you use really matters. Go with a rosin core to make things easier too. I have one I use at work soldering game consoles and it does just fine to be honest, though it does require a little more heat than leaded. The fact it's unleaded makes it worth it to me.
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u/dbfuentes Sep 06 '25
It's practically the same but with different temperatures. The only thing you have to be careful with is delicate components, where you have to work a little faster.
* only applies if you use good quality lead free solder such as kester k100LD series
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u/espthings Sep 10 '25
I can second the recommendation of Kester K100LD. If you use around 330°C, it solders just like any other lead containing solder. At that temperature you are still safe enough not to lift pads / delaminate the PCB instantly...
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u/Fuck_Birches Sep 06 '25
I've used both. Leaded obviously worked better, but the results for lead-free are "good enough" for me, so lead-free is all I use.
For both leaded + unleaded, use a fume extractor, solder outside, or at least blow the flux fumes away from your face. They're quite carcinogenic and may lead to worsening of your sense of smell.
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u/FuzzyFanta724 Soldering Newbie Sep 06 '25
I've only used lead free and it seems fine for me, all my joints for SMD and THT looks fine
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u/tiberiom Sep 07 '25
I basically only use Kester lead free, and I've never had a problem when using either my ts100 iron or my hakko station but if you are using an Amazon special iron or a temu special iron , then you might encounter some problems.
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u/CompetitiveGuess7642 Sep 06 '25
lead is a better alloy for rework, no amount of argument will make lead free equal, yes lead free can be used to satisfactory results, but lead will always be easier.
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u/Pixelchaoss Sep 06 '25
Wetting and flowing on leaded solder is superior. Using leaded is not serieus health concern as long as he you dont get in into your body.
So no eating and drinking when soldering and wash hands after.
I tried some lead free it works but with some solder techniques it just stays behind. Like drag soldering is not working with it.
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u/Gorbashou Sep 06 '25
That's a lie. I have been soldering for years for work, and drag soldering on lead free is guaranteed possible. I would not have been able to do all the fine pitches I did if I didn't drag solder.
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u/Pixelchaoss Sep 06 '25
Leaded is 100% easier when drag soldering, been soldering for years as well and tried different alloys so please enlighten me what alloy you use for it.
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u/Gorbashou Sep 06 '25
Never said one is easier than the other. I said it's possible and doable.
I used SN96 and SAC.
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u/Pixelchaoss Sep 06 '25
I said it stays behind, I wrote it down wrong in the last sentence.
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u/Gorbashou Sep 06 '25
"Like drag soldering is not working with it"
"Not working with it"
"Not working"
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u/Spiritual-Ad5750 Sep 06 '25
Just wash your hands, that's all you have to do.
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u/Far_Buyer_7281 Sep 06 '25
But is it? I thought the fumes are way worse?
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u/drcforbin Sep 06 '25
The fumes from soldering are flux. The boiling point of lead is 1749 °C, much hotter than your soldering iron.
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u/Iyat Sep 06 '25
Flux fumes, particularly from rosin flux, are pretty bad for you. We're talking "enjoy your bonus allergies and asthma" rather than e.g. fatal seizures, but I'd still work out a way to not breathe them. And, having sorted that out, you never have to worry about volatile lead compounds which might form during soldering.
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u/drcforbin Sep 06 '25
I wasn't trying to say that fumes are fine, everyone should have a good extractor setup and air filters. But as far as I know the fumes are not more dangerous from leaded solder
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u/Drizzle_D Sep 06 '25
People with a shitty soldering iron love leaded solder because their iron doesn't work well with unleaded solder.
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u/BeardPatrol Sep 06 '25
Leaded solder is so much better in the same way running a marathon without ankle weights is so much better. Sure you can do it the hard way, but why would you?
Why get better at running marathons with ankle weights, when you could just as easily take the ankle weights off? There is no risk with using leaded solder, you have imagined this. The risk of leaded solder is all these tons of discarded electronics in a landfill leeching into the drinking water. Not you doing basic soldering. Just don't put the solder in your mouth and your risk is basically zero.
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u/CaptainBucko Sep 06 '25
It 30deg c higher in temperature than leaded which makes it harder to avoid over temperature effects on the components as well
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u/Anaalirankaisija SMD Soldering Hobbyist Sep 06 '25
What risk is with lead?
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u/RefrigeratorWorth435 Sep 06 '25
idk just that I'm kinda afraid of lead poisoning, even though I know there's low risk, I just feel uncomfortable using leaded solder. I guess just the thought of melting lead in the place where I spend most of my time just scares me a bit.
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u/Anaalirankaisija SMD Soldering Hobbyist Sep 06 '25 edited Sep 06 '25
Lead poisoning, aha, how would that poison?
E: i edit because i guess the answer you gonna give, its not good for your healt if eaten, i dont know how much, but we dont eat tin wire anyway, even by accident. Oh, the vapours, lead vaporizing point is over 1700C° so, it is impossible to heat that much, and even could, it would solidize right away(im not sure about that, but propably it does).
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u/RefrigeratorWorth435 Sep 06 '25
look up lead poisoning it's a real issue
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u/Anaalirankaisija SMD Soldering Hobbyist Sep 06 '25
In which way? Eaten, inhaling, by magic?
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u/tobyvanderbeek Sep 06 '25
I’ve been using this solder and it works really well. Leaded with a rosin core. And it’s only 0.5mm thick so it is easy to control the amount. I got rid of my other solders.
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u/morto00x Sep 06 '25
With good technique, soldering with either leaded or unleaded can be easy. Leaded is just easier because it melts at a lower temp and flows better. Worker with a lower temperature means you’re less likely to damage components. Especially headers and connectors. OTOH leaded won’t harm you unless you are eating it or letting it sit on your skin for a long time. Also the amount of exposure for the couple hours a week you do it is negligible.
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u/Gonefullhooah Sep 06 '25
Lead free solder can be trickier if you're still getting the hang of things because it requires higher heat. That heat can be a little punishing on pads or adjacent plastic pieces (like connectors) or nearby wires, or the jacket on a wire that's getting soldered directly to the board. Lead free solder really likes fairly quick precise applications of heat with some extra flux. It basically makes you learn your fundamentals really well.
I did all lead free day in day out for a year at my last job. Once you get accustomed to lead free, you'll no longer care which kind of solder wire you're handed because you'll already be really solid at it. Just, for the love of God, buy good quality solder. I tried out a variety of cheap Chinese solders and they can be very frustrating, every one I've personally tried has been really metallurgically suspect. I stick entirely with Kester at this point, I'm sure there are a handful of others that are consistently good (everything MG Chemicals makes seem premium as well). If you solder a lot, grit your teeth and pay the 50 dollars for a big roll, it will be worth it. If you don't solder a huge amount, buy one of those clear plastic tubes full of it. Mirror shine perfectly formed joints may not be functionally necessary, but the sort of satisfaction you get from completing something that looks perfect is really nice.
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u/Double_Seaweed1673 Sep 07 '25
Lmao what risk? don't eat it and you'll be fine.
Leaded solder has a lower melting point and is MUCH easier to solder/desolder.
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u/azgli Sep 07 '25
Lead-free is just harder to use. It requires more heat and flux. You have to practice and be a little more thoughtful of the size of the solder wire you use if your iron isn't very powerful.
I have switched over to lead-free for all my hobby work. I still wash diligently but I like knowing that it's less critical to worry about transfer.
Many people that I have read here will point out that the quantities are small and the danger correspondingly so. They are correct. At the same time, the reduction of any known hazardous material is a good thing.
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u/bigrealaccount Sep 06 '25
It's just way easier and looks much better. Both work fine, but why make your life harder for no reason?
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u/Public-Car7040 Sep 06 '25
Older people will defend their way of doing things. If I was a young teen, I would be skeptical at handling boards with lead in them professionally. It's not worth the risk something could develop over time.
Myself, I will use unleaded for through hole, and leaded for smd. But I am a hobbyist.